I've been following this issues and feel that those of us who are not accusomed to thinking in ppm (parts per milliion) just lose track of how small the quantities are that are needed, not necessarily as actual nutrients, sometimes, but as catalysts for necessary metabolic processes. For example, copper, as a micronutrient or catalyst as needed for most plants is given in sufficient quantity by the amount dissolved from the brass fitting on the end of one's hose . Think about that little fact for a while. We are so accustomed to converse about millions, and billiions, (of dollars)etc. that we don't really know what we're doing when we talk "real money", or when these terms get translated into other venues. If you counted as fast as you could for every hour of your life, sequentially, in the manner 1, 2, 3, 4...n...you could not count to a billion in your lifetime. MICROnutrients are those elements that are needed in very, very small amounts--we're talking molecular chemistry here, not teaspoons per plant, but more like a teaspoon per 100 square feet, or more. Water, even neutral water, running over granite will dissolve micronutrients, sufficient for many plants, acid rain will release much more. Ordinary water, together with humic acid from fallen organic detritus and wind-blown rock dust brings many nutrients. Incidentally, I concur with Jim Shields on Osmani's mystery hippeastrums, (Dutch cultivars) ; with John Lonsdale and others who pointed out that muriate of potash is KCl. And, I don't make allowances for a cultural difference here, between countries. K2SO4 is not muriate of potash, but potassium sulphate, regardless of the country. Somebody there is misinformed just as we are here, from time to time, and for some of us--much of the time. The facts of chemistry do not change when one goes from the US to Germany, or Russia or Argentina. Adam Fikso in Glenview, IL .USDA Zone 5a